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У транс-женщин на гормонах риск рака груди в 46 раз выше, чем у мужчин, — но всё же ниже, чем у женщин

Риск рака молочной железы у трансгендерных людей, получающих гормональное лечение: общенациональное когортное исследование в Нидерландах

Когортные и регистровые исследованияКросс-секс гормоны
Authors
Christel J.M. de Blok, Chantal M. Wiepjes, Nienke M. Nota, Klaartje van Engelen, Muriel A. Adank, Koen M.A. Dreijerink, Ellis Barbé, Inge R.H.M. Konings, Martin den Heijer
Journal
BMJ
Year
2019
Source
https://doi.org/10.1136/bmj.l1652

Summary

Researchers used records from the Amsterdam gender clinic, which treats over 95% of Dutch transgender patients, linked to the national record of cancer diagnoses. They counted breast cancers in about 3,500 people on cross-sex hormones. Trans women got breast cancer far more often than men normally do (about 46 times), but still less often than women. Their tumours looked like the typical hormone-sensitive breast cancers seen in women. This suggests estrogen, and possibly the testosterone-blocking drug cyproterone acetate, shifts risk toward the female pattern. Trans men had a lower risk than women, likely helped by having had their breasts removed. The authors concluded the overall risk is low and normal screening is enough. With only 15 and 4 cases, missing data on major risk factors, and comparisons with the general population, the numbers are rough.

Key findings

  • Исследование наблюдало 2 260 транс-женщин и 1 229 транс-мужчин на гормональном лечении, что в сумме составило около 34 000 и 15 000 лет наблюдения.
  • У транс-женщин было 15 случаев рака груди после типичных 18 лет на гормонах (диапазон от 7 до 37 лет), типично в возрасте 50 лет.
  • Рак груди у транс-женщин встречался примерно в 46 раз чаще, чем у мужчин (вероятно, от 27 до 75 раз), но лишь примерно в три раза реже, чем у женщин.
  • Большинство опухолей у транс-женщин были гормоночувствительного типа (83% питались эстрогеном, 67% — прогестероном), как те, что обычно наблюдаются у женщин.
  • У транс-мужчин было 4 случая рака груди, примерно в пять раз реже, чем у женщин, но в 59 раз чаще, чем у мужчин; три случились спустя годы после удаления груди.
  • Исследователи не могли сравнить разные гормональные препараты, потому что лечение часто менялось, а большинство транс-женщин принимали ципротерона ацетат.
  • Авторы заключили, что обычных правил скрининга груди достаточно для трансгендерных людей на гормонах.

Abstract

OBJECTIVE: To investigate the incidence and characteristics of breast cancer in transgender people in the Netherlands compared with the general Dutch population. DESIGN: Retrospective, nationwide cohort study. SETTING: Specialised tertiary gender clinic in Amsterdam, the Netherlands. PARTICIPANTS: 2260 adult trans women (male sex assigned at birth, female gender identity) and 1229 adult trans men (female sex assigned at birth, male gender identity) who received gender affirming hormone treatment. MAIN OUTCOME MEASURES: Incidence and characteristics (eg, histology, hormone receptor status) of breast cancer in transgender people. RESULTS: The total person time in this cohort was 33 991 years for trans women and 14 883 years for trans men. In the 2260 trans women in the cohort, 15 cases of invasive breast cancer were identified (median duration of hormone treatment 18 years, range 7-37 years). This was 46-fold higher than in cisgender men (standardised incidence ratio 46.7, 95% confidence interval 27.2 to 75.4) but lower than in cisgender women (0.3, 0.2 to 0.4). Most tumours were of ductal origin and oestrogen and progesterone receptor positive, and 8.3% were human epidermal growth factor 2 (HER2) positive. In 1229 trans men, four cases of invasive breast cancer were identified (median duration of hormone treatment 15 years, range 2-17 years). This was lower than expected compared with cisgender women (standardised incidence ratio 0.2, 95% confidence interval 0.1 to 0.5). CONCLUSIONS: This study showed an increased risk of breast cancer in trans women compared with cisgender men, and a lower risk in trans men compared with cisgender women. In trans women, the risk of breast cancer increased during a relatively short duration of hormone treatment and the characteristics of the breast cancer resembled a more female pattern. These results suggest that breast cancer screening guidelines for cisgender people are sufficient for transgender people using hormone treatment.

Conclusion

This large nationwide cohort study in the Netherlands showed an increased risk of breast cancer in trans women compared with cisgender men. The risk in trans women is still lower than in Dutch cisgender women and resembles a more female type of breast cancer and hormone receptor status. In trans men, a lower risk compared with Dutch cisgender women was observed. Based on this study, we conclude that the absolute overall risk of breast cancer in transgender people remains low and therefore it seems sufficient for transgender people using hormone treatment to follow screening guidelines as for cisgender people. As the risk of breast cancer in trans women increased during a relatively short duration of hormone treatment, it would be worthwhile for future studies to investigate in more detail the cause of breast cancer in transgender people receiving hormone treatment.